The unique properties of hNT-Neurons, pure human post mitotic neuronal cells, justify their development as a local delivery system for dopaminergic factors of therapeutic benefit in Parkinson's disease. Previous research demonstrates that hNT-Neurons are transplantable and transfectable. Transplants of hNT-neurons into rodent brain show cell survival, neuronal phenotype, and functional integration. Transfection studies suggest that recombinant hNT-neurons can achieve efficient and stable gene expression. The aims of this proposal are to: evaluate the endogenous dopaminergic properties of hNT-Neurons; enhance dopaminergic activity with enzymes, cofactors or growth factors; survey additional clones and subclones for highest production; and identify the optimal gene construct to transfect for therapeutic purposes. Enzyme expression and L-dopa production will be measured using immunochemical and biochemical assays. This research strategy allows for characterization and optimization of the dopaminergic properties of hNT-Neurons in vitro prior to animal studies planned in Phase II. Functional, dopaminergic, human neuronal cells are scientifically promising, technologically superior to other cell systems, and commercially viable as a treatment for Parkinson's disease.